Modeling and Numerical Simulation of the Recurrence of OzoneDepletion Events in the Arctic Spring

Abstract. This paper presents a numerical study of the recurrences (or oscillations) of tropospheric ozone depletion events, ODEs, using the further developed one-dimensional chemistry transport model KINAL-T. Reactive bromine is the major contributor to the occurrence of ODEs. After the termination of an ODE, the reactive bromine in the air is deposited onto aerosols or on the snow surface, and the ozone may regenerate via NO x -catalyzed photochemistry or by turbulent transport from the free troposphere into the boundary layer. The replenished ozone then is available for the next cycle of autocatalytic bromine release (bromine explosion) leading to another ODE. The recurrence periods are found to be as low as five days for the purely chemically NO x -driven oscillation and 30 days for a diffusion-driven recurrence. An important requirement for recurrences of ODEs to occur is found to be a sufficiently strong inversion layer. In a parameter study, the dependence of the recurrence period on the nitrogen oxides concentration, the inversion layer strength, the ambient temperature, the aerosol density, and the solar radiation is investigated. Parameters controlling the recurrence of ODEs are discussed.